EFFECT OF POLYMERIZATION TEMPERATURE ON THE MICROTACTICITY OF ISOTACTIC POLY(PROPYLENE) PREPARED USING HETEROGENEOUS (MGCL2-SUPPORTED) ZIEGLER-NATTA CATALYSTS

A study of the effect of polymerization temperature on the microtactic ity of poly(propylene) prepared using various MgCl2-supported catalyst s has shown that, in almost all cases, an increase in temperature lead s not only to higher proportions of isotactic polymer but also to incr eased stereoregularity of the isotactic fraction. The results indicate a greater relative increase in productivity, with increasing temperat ure, for highly isospecific as opposed to moderately isospecific centr es. It is suggested that easier propagation after the occasional regio irregular (2,1-) insertion may contribute to this effect.